The present invention relates to personal wash cleanser compositions comprising an .alpha.-hydroxy benefit agent which in turn comprises mixtures of both short chain (C.sub.1 -C.sub.12) and long chain (C.sub.14 -C.sub.24) .alpha.-hydroxy acid esters. More specifically, by combining the longer term moisturizing effect of short chain esters, (note, short chain esters such as ethyl (S)-, butyl (S)- or octyl (S)-lactate often have initial drying effect) with the shorter term moisturizing/masking benefit of long chain esters (e.g., octadecyl (S)-lactate), applicants have obtained superior compositions. Mixing both short and long term moisturizing effects allows compositions to be prepared which have long term beneficial effects while providing short term visual tactile effects of soft, smooth skin. More specifically, applicants have been able to mix short chain esters (normally drying) with long chain esters and significantly reduce the drying effect of the short chain esters while providing longer term moisturizing effects associated with the shorter chain esters.
The use of short chain .alpha.-ahydroxy acid esters (e.g., C.sub.1 to C.sub.4 alkyl lactates to treat acne) or long chain .alpha.-hydroxy acid esters (e.g., long chain lactate ester emollient) is broadly taught in the art. No art, however, teaches a specific combination of long and short chain esters of .alpha.-hydroxy acid (e.g., lactic acid) or that, in combination, the long and short chain esters could provide multiple benefit.
Typical of this art is U.S. Pat. No. 4,540,567 to Oneto et al. (assigned to Lever Brothers), which teaches compositions comprising short chain C.sub.1 -C.sub.4 lactate (primarily for treatment of acne) or mixtures which are dissolved in a mixture of water and water-miscible C.sub.2 -C.sub.4 alkylene glycol or a polymer thereof. Alkylene glycol is said to act as a vehicle to help limit dehydration of skin and improve sensory feel of product. There is no teaching or suggestion of combining with long chain .alpha.-hydroxy acid esters or that by doing so dehydration effect can be ameliorated.
It is thus one object of the invention to provide a unique composition which provides the long term moisturizing benefits provided by short chain length .alpha.-hydroxy acids while at the same time masking the short term dryness often caused by the short chain esters by using long chain esters of .alpha.-hydroxy acids to provide short term moisturizing benefits.